Clipping device



Sept. 10, 1968 K. A. KLENZ I CLIPPING DEVICE Filed May 29, 1967' rill-IINVENTOR. KARL A. KLENZ g g, M.

United States Patent "ice 3,400,433 CLIPPING DEVICE Karl A. Klenz,Oakland, Calif., assignor to Rheem Manufacturing Company, New York,N.Y., a corporation of California Filed May 29, 1967, Ser. No. 642,028 7Claims. (Cl. 24-305) ABSTRACT OF THE DISCLOSURE A deformable generallyU-shaped sealing clip for providing a tight seal around the neck of aflexible container. The clip is shaped to provide a cross section ofoptimum strength with a relatively flat side against the material of thecontainer neck.

This invention relates to apparatus for applying a deformable sealingclip around the mouth of a flexible container such as a sausage casing,plastic bag, and the like. More particularly the invention is directedto a generally U-shaped deformable sealing clip adapted to be appliedaround the neck of a flexible container for providing an air tight sealsuch as is required when the container is evacuated to maintain theproduct therein under a vacuum.

In the packaging of vacuum packed products, such as meat, cheese,poultry, and the like, it is essential that a perfect seal be applied soas to prevent spoilage of the product by the leakage of air into thecontainer. Heretofore numerous attampts have been made to improveclipping apparatus and sealing clips to the end that optimum sealingeffect is achieved. The most important advance in this art has been theprovision of the so called cross over clip which comprises a U-shapedclip deformed around the mouth or neck of the container so that theopposed legs of the clip cross each other during the deforming step andare brought into side by side closely adjoining relationship. Theimportance of the cross over type of clip is set forth in some detail inUS. Patent No. 3,266,138. Cross over type clips are also disclosed inUS. Patents Nos. 2,265,277, 2,682,054, 1,963,306, 2,130,779, 3,026,521,3,210,835, 3,224,083, 3,239,926, and 3,293,736.

In those applications wherein extended shelf life of a hermetic seal isnot essential it has been customary in the past to apply what isgenerally known as a butt type clip. Such butt type clips are usuallymade from broad fiat material and are also generally U-shaped andapplied to the material to be sealed by urging the legs of the cliptoward the crown of the clip which connects the opposite legs together.Such fiat butt type clips have a relatively low section modulus and havenot been dependable in effecting an air tight seal and their functionhas been usually restricted to merely providing a closure for thecontainer. Examples of such butt type clips may be seen in US. PatentsNos. 2,639,875, 2,700,805, 2,756,428, 2,812,628, 2,855,647, and2,972,747.

As pointed out in the above noted Patent No. 3,266,138, it is importantin providing an air tight seal to apply extremely high radially inwardlydirected compressive forces on the material of the container mouth inorder to 3,400,433 Patented Sept. 10, 1968 prevent leakage. This isespecially true in the case of bags and other containers made of moderntough resilient plastics. When a clip is applied to seal the neck of acontainer formed of relatively frangible material, such as cellulose,the application of high radially inwardly directed pressures has, inmany instances, resulted in such material being crushed and severedthereby destroying it for its intended purpose.

The above noted crushing effect is in part attributable to the fact thatwire of a round cross section has been used almost uniformly in theprior art for providing cross over clips. In this connection it will beapparent that the inner element of a U-shaped clip formed of wire ofcircular cross section is a U-shaped line which engages the materialfirst as the clip is deformed into a closed loop surrounding the mouthof the container. The fact that the material of the container isextremely flexible would suggest that the particular cross section ofthe wire from which the clip is formed is not of any particularsignificance, however, it has actually been found that a substantialreduction in the unit pressure on the material may be effected by makingthe inner side of the U-shaped clip flat instead of semicircular as isthe case in the clip made of wire of circular cross section.

It has also been found that the sealing effect of a clip is proportionalto the width of the clip as well as the radially inwardly directedpressure which the clip exerts. Flat clips of the nontight type areusually quite wide, but as noted above no successful attempt has beenmade in the past to make such clips sufliciently tight to retain theseal of a vacuumized bag, especially when one clip size is employed toseal different amounts of material. Furthermore, the section modulus ofsuch flat clips is usually insufficient to resist the outwardly directedpres sure of the material tending to open the seal.

The main object of the present invention is the provision of a novelclip which lends itself to use in creating an efficient seal around theneck of a flexible container and at the same time is less likely thanprior art clips to cause failure of the material when the necessarilyhigh pressures are applied to such material.

Another object of the invention is the provision of an improved clip foruse either as a nontight or air tight seal and made of wire of a crosssection satisfying most of the practical requirements existing inapparatus of the subject type.

Another object of the invention is the provision of a novel sealing clipwhich is adapted to effect a better air tight seal than has heretoforebeen possible and without any increase in expense of making the clip.

Other objects and advantages will be apparent from the followingspecification and from the drawings.

FIG. 1 is a semischematic side view showing a clip of the presentinvention with the associated punch and die at the point at which thelegs of the clip are about to be deformed inwardly toward each other.

FIG. 2 is a greatly enlarged typical cross section through one form ofthe clip.

FIG. 3 is a similar cross section through the preferred form of clipcontemplated by the present invention.

FIG. 4 is a cross section similar to FIG. 3 showing a modified formthereof.

FIG. 5 is a cross section through the mouth of a sealed containershowing the clip deformed therearound.

FIG. 6 is a fragmentary side elevation of a sausage casing showing theclip of FIG. 3 applied thereto.

As is described in greater detail in US. Patent No. 3,266,138, the clipgenerally designated 10 is adapted to be urged against a die A by apunch B in order to deform the clip around the neck C of the containerto be sealed. Referring to FIG. 1 the undeformed clip 10 comprises apair of opposed legs 11, 12 which are connected together at one of theircorresponding ends by a crown 13 joined to said legs by curved junctures14, 15. The legs 11, 12 are straight and may be considered parallelexcept that it is preferable that they flare outwardly slightly at theirfree ends to facilitate controlled feeding of the clip along the feedtrack (not shown). The crown piece 13 is straight and may be consideredperendicular to the axes of legs 11 and 12. The junctures 14, 15 areformed to a relatively sharp radius but one that is sufliciently largeso as not to distort the wire excessively during the bending operationof forming the clip. The clip may be formed of various materials,including steel and aluminum, and it is preferably cold worked to theshape shown in FIG. 1. The cross section of the clip 10, shown in FIG.2, is generally triangular with rounded corners and is uniformthroughout its length. The cross sectional contour of the clip is suchthat a relatively wide side is presented to the material to becompressed and sealed. The remaining sides 21, 22 converge away from theinner side 20. It is therefore apparent that the extremely highlocalized pressures which attend the use of a clip of circular crosssection are not present and the clamping forces are spread over theentire width W of the clip. As pointed out above, not only is the flatside 20 desirable for the purpose of minimizing localized stress but theincrease in width of the inner side of the clip in a direction along theneck of the bag increases the sealing effect and thereby reduces thelikelihood of the container leaking.

As an example it has been found that in a clip formed to a cross sectionas shown in FIG. 2 with the width W equal to .1" and the depth of thesection D equal to .1" the resultant sealing effect is improved over aclip of round cross section having a diameter of .07" and an equivalentsection modulus.

Another important feature of the cross section of the clip shown in FIG.2 is that the unit tensile strength is not as great as in a clip ofcircular cross section since the deformed clip is in effect a curvedbeam (FIG. 5) and as such should have more material adjacent its centerof curvature than at a point further away from said center. For thisreason excessive stresses and deflections of the fibers of the materialare avoided.

Another advantage of the section of FIG. 2 resides in the fact that theclip is more easily controlled while feeding the same along the feedchannel of the clipping device than a clip of circular cross section.

The strength of the clip may be enhanced and certain additionaladvantages obtained by the preferred form of cross section shown in FIG.3. In this case the section 10' is trapezoidal with the width of thenarrower side 23 being preferably at least one half the maximum width Wof the inner side 24 which engages the material to be sealed. The depthD of the cross section may be substantially equal to the width W. Itwill be apparent that the section modulus of the trapezoidal section isconsiderably greater than the section modulus of the triangular sectionand, in fact, is more than twice as great. For this reason theresistance of the closed clip to opening under the radially outwardlydirected pressure of the deformed material of the container issubstantially greater than the corresponding resistance of a clip ofcircular cross section having an equivalent area.

As an example, if the width W and the depth or thickness D are each madeequal to .1", the section modulus about its neutral axis of the sectionof FIG. 3 is greater than the corresponding section modulus of acircular section of .1" diameter. It will be understood that the generalcomparison of resistance to bending of trapezoidal and round clipsremains about the same even if the neutral axis is moved toward theinner side 24 as is the case if the loop of FIG. 5 is considered to be acurved beam.

As is the case with the triangular clip of FIG. 2, the trapezoidal clipof FIG. 3 has the advantage of being easily controlled while being fedalong the clip channel of the feed track. In this connection it will benoted that the converging sides 25, 26 of the clip present fiat surfacesadapted to be engaged by complementarily formed inner sides of the feedtrack. It is therefore not necessary to engage the clip during feedingalong the outer side 23 and said outer side is available for imprintinga code number on the clip to identify, for example, the plant in whichthe product is manufactured. Since the outer side 23 need not engage thetrack channel there is no likelihood of the imprinted indicia beingsmeared or otherwise damaged during the deforming step.

The clip of the present invention also has the advantage of providing aflat surface on the outer sides of the clip so that an adhesive tape forsecuring together a plurality of clips engages a greater area than inthe case of a clip of circular cross section.

With some materials it has been found that an increase in sealing effectmay be obtained by providing a relatively small groove along the innerside of the clip as shown in FIG. 4. In this case the clip 10" issubstantially the same as that shown in FIG. 3 except that the wire ofthe clip is formed with a shallow longitudinally extending groove 27along the inner face 28. With extremely resilient materials it has beenfound that relief of the high pressures resulting from the deformationof the clip is obtained without impairment of the sealing effect by theincorporation of the groove 27.

The use of the above described clip for sealing a vacuumized containerhas been emphasized because such use presents the greatest problems.However it will be understood that the clip is equally applicable toother uses. For example, in many instances the container is subjected tointernal pressure rather than a vacuum. In such cases the improvedresistance of the clip to opening under the internal pressure at theneck is equally advantageous. Similarly, in those instances where theweight of the contents is applied to the clip, as when the product issuspended, the resistance of the clip to slipping along the length ofthe container neck is especially important. As pointed out above theform of FIG. 4 is particularly advantageous in this latter application.

The very specific description given above of the preferred form of theinvention is not to be taken as restrictive as it will be apparent thatvarious modifications will occur to those skilled in the art withoutdeparting from the scope of the following claims.

I claim:

1. A fastener for forming a tight seal around an article such as themouth of a flexible container comprising:

a clip being initially generally U-shaped having a pair of opposed legsand a crown connecting the corresponding ends of said legs,

said legs being adapted to be deformed toward each other into encirclingrelation with such article,

said clip being formed of wire of generally uniform cross sectionthroughout its length and being shaped to provide one substantially flatarticle engaging side inner side directed inwardly of said clip and apair of opposite sides converging outwardly of said clip from said oneside.

2. A fastener according to claim 1 wherein said inner side is providedwith a groove extending along the entire length of said inner side.

3. A fastener according to claim 1 wherein the cross sectional contourof said wire is generally in the form of a triangle with rounded cornersconnecting the sides of said triangle.

4. A fastener according to claim 1 wherein the thickness of said clip ina direction at right angles to said one side is substantially equal tothe width of said one side.

5. A fastener according to claim 1 wherein the cross sectional contourof said clip is substantially trapezoidal.

6. A fastener according to claim 5 wherein the width of the sideopposite said inner side is about one half the width of said inner side.

7. A fastener according to claim 6 wherein the depth of said clip atright angles to said inner side is sul'ficiently great that the sectionmodulus of the cross sectional area about its neutral axis issubstantially equal to the corresponding section modulus of a circulararea having a diameter equal to the width of said inner side.

References Cited UNITED STATES PATENTS 647,693 4/ 1900 Blantz. 2,972,7912/1961 Kelem 24-30.5 3,266,138 8/1966 Tipper 85-49 XR FOREIGN PATENTS717,308 10/1931 France.

793,126 4/1958 Great Britain.

985,012 3/1965 Great Britain.

529,968 6/ 1955 Italy.

DONALD A. GRIFFIN, Primary Examiner.

